phaser
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A fast, free and fun HTML5 Game Framework for Desktop and Mobile web browsers.
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JavaScript
/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2020 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|MIT License}
*/
var Class = require('../../../utils/Class');
/**
* @classdesc
* A zone that places particles on a shape's edges.
*
* @class EdgeZone
* @memberof Phaser.GameObjects.Particles.Zones
* @constructor
* @since 3.0.0
*
* @param {Phaser.Types.GameObjects.Particles.EdgeZoneSource} source - An object instance with a `getPoints(quantity, stepRate)` method returning an array of points.
* @param {number} quantity - The number of particles to place on the source edge. Set to 0 to use `stepRate` instead.
* @param {number} stepRate - The distance between each particle. When set, `quantity` is implied and should be set to 0.
* @param {boolean} [yoyo=false] - Whether particles are placed from start to end and then end to start.
* @param {boolean} [seamless=true] - Whether one endpoint will be removed if it's identical to the other.
*/
var EdgeZone = new Class({
initialize:
function EdgeZone (source, quantity, stepRate, yoyo, seamless)
{
if (yoyo === undefined) { yoyo = false; }
if (seamless === undefined) { seamless = true; }
/**
* An object instance with a `getPoints(quantity, stepRate)` method returning an array of points.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#source
* @type {Phaser.Types.GameObjects.Particles.EdgeZoneSource|Phaser.Types.GameObjects.Particles.RandomZoneSource}
* @since 3.0.0
*/
this.source = source;
/**
* The points placed on the source edge.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#points
* @type {Phaser.Geom.Point[]}
* @default []
* @since 3.0.0
*/
this.points = [];
/**
* The number of particles to place on the source edge. Set to 0 to use `stepRate` instead.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#quantity
* @type {number}
* @since 3.0.0
*/
this.quantity = quantity;
/**
* The distance between each particle. When set, `quantity` is implied and should be set to 0.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#stepRate
* @type {number}
* @since 3.0.0
*/
this.stepRate = stepRate;
/**
* Whether particles are placed from start to end and then end to start.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#yoyo
* @type {boolean}
* @since 3.0.0
*/
this.yoyo = yoyo;
/**
* The counter used for iterating the EdgeZone's points.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#counter
* @type {number}
* @default -1
* @since 3.0.0
*/
this.counter = -1;
/**
* Whether one endpoint will be removed if it's identical to the other.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#seamless
* @type {boolean}
* @since 3.0.0
*/
this.seamless = seamless;
/**
* An internal count of the points belonging to this EdgeZone.
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#_length
* @type {number}
* @private
* @default 0
* @since 3.0.0
*/
this._length = 0;
/**
* An internal value used to keep track of the current iteration direction for the EdgeZone's points.
*
* 0 = forwards, 1 = backwards
*
* @name Phaser.GameObjects.Particles.Zones.EdgeZone#_direction
* @type {number}
* @private
* @default 0
* @since 3.0.0
*/
this._direction = 0;
this.updateSource();
},
/**
* Update the {@link Phaser.GameObjects.Particles.Zones.EdgeZone#points} from the EdgeZone's
* {@link Phaser.GameObjects.Particles.Zones.EdgeZone#source}.
*
* Also updates internal properties.
*
* @method Phaser.GameObjects.Particles.Zones.EdgeZone#updateSource
* @since 3.0.0
*
* @return {this} This Edge Zone.
*/
updateSource: function ()
{
this.points = this.source.getPoints(this.quantity, this.stepRate);
// Remove ends?
if (this.seamless)
{
var a = this.points[0];
var b = this.points[this.points.length - 1];
if (a.x === b.x && a.y === b.y)
{
this.points.pop();
}
}
var oldLength = this._length;
this._length = this.points.length;
// Adjust counter if we now have less points than before
if (this._length < oldLength && this.counter > this._length)
{
this.counter = this._length - 1;
}
return this;
},
/**
* Change the source of the EdgeZone.
*
* @method Phaser.GameObjects.Particles.Zones.EdgeZone#changeSource
* @since 3.0.0
*
* @param {Phaser.Types.GameObjects.Particles.EdgeZoneSource} source - An object instance with a `getPoints(quantity, stepRate)` method returning an array of points.
*
* @return {this} This Edge Zone.
*/
changeSource: function (source)
{
this.source = source;
return this.updateSource();
},
/**
* Get the next point in the Zone and set its coordinates on the given Particle.
*
* @method Phaser.GameObjects.Particles.Zones.EdgeZone#getPoint
* @since 3.0.0
*
* @param {Phaser.GameObjects.Particles.Particle} particle - The Particle.
*/
getPoint: function (particle)
{
if (this._direction === 0)
{
this.counter++;
if (this.counter >= this._length)
{
if (this.yoyo)
{
this._direction = 1;
this.counter = this._length - 1;
}
else
{
this.counter = 0;
}
}
}
else
{
this.counter--;
if (this.counter === -1)
{
if (this.yoyo)
{
this._direction = 0;
this.counter = 0;
}
else
{
this.counter = this._length - 1;
}
}
}
var point = this.points[this.counter];
if (point)
{
particle.x = point.x;
particle.y = point.y;
}
}
});
module.exports = EdgeZone;